Serplulimab, a novel anti-PD-1 antibody, plus chemotherapy versus chemotherapy alone as first-line treatment for extensive-stage small-cell lung cancer: An international randomized phase 3 study.
Authors: Ying Cheng, Liang Han, Lin Wu, Jun Chen, Hongmei Sun, Guilan Wen, Yinghua Ji, Mikhail Dvorkin, Jianhua Shi, Zhijie Pan, Jinsheng Shi, Xicheng Wang, Yuansong Bai, Tamar Melkadze, Yueyin Pan, Xuhong Min, Maksym Viguro, Yan Xu, Qingyu Wang, Jun Zhu
Journal: Journal of Clinical Oncology (2022)

8505 Background: Monoclonal antibodies against programmed death-ligand 1 (PD-L1) have been approved for the first-line treatment of extensive-stage small-cell lung cancer (ES-SCLC) in combination with chemotherapy. However, whether a programmed death 1 (PD-1) inhibitor provides similar survival benefit in this patient population remains unclear. In this study, the efficacy and safety of serplulimab, a novel humanized monoclonal anti-PD-1 antibody, were assessed in combination with chemotherapy in previously untreated ES-SCLC patients. Methods: In this international, randomized, double-blind, multicenter, phase 3 trial (NCT04063163), patients with ES-SCLC who had not received prior systemic therapy were randomized (2:1) to receive serplulimab 4.5 mg/kg or placebo intravenously every 3 weeks. All patients received intravenous carboplatin and etoposide every 3 weeks for up to 4 cycles. The primary endpoint was overall survival (OS). Secondary endpoints included progression-free survival (PFS), objective response rate (ORR), duration of response (DoR), and safety. Results: Between September 12, 2019 and April 27, 2021, 585 patients were randomized (serplulimab group, n = 389; placebo group, n = 196). At interim analysis, the median follow-up duration was 12.3 months. Median OS was significantly prolonged in the serplulimab group than the placebo group (15.4 vs.10.9 months; hazard ratio [HR] 0.63, 95% CI 0.49–0.82; P &lt; 0.001). Median PFS assessed by the independent radiology review committee (IRRC) per RECIST v1.1 was significantly longer in the serplulimab group than the placebo group (5.8 vs. 4.3 months; HR 0.47, 95% CI 0.38–0.59; P &lt; 0.001). Efficacy improvements were also observed in ORR (80.2% vs. 70.4%) and DoR (5.6 vs. 3.2 months) as assessed by IRRC per RECIST v1.1. Grade ≥3 treatment-emergent adverse events (TEAEs) related to serplulimab or placebo were reported in 129 (33.2%) and 54 (27.6%) patients in the respective groups. Incidence of immune-related TEAEs was higher in the serplulimab group compared to the placebo group (37% vs. 18.4%), with the largest difference in endocrine disorders (18.3% vs. 4.6%), which are commonly reported with anti-PD-1/PD-L1 therapies. Four deaths (1 acute coronary syndrome, 1 pyrexia, and 1 platelet count decreased in the serplulimab group; 1 thrombocytopenia in the placebo group) that might be related to study drugs were reported. Conclusions: Serplulimab plus chemotherapy as first-line treatment provided significant benefits and a manageable safety profile compared with chemotherapy alone in ES-SCLC patients. For the first time, OS benefits was demonstrated with a PD-1 inhibitor in a global phase 3 study among previously untreated ES-SCLC patients. Clinical trial information: NCT04063163.